I think something people are forgetting is that not all watermelons are striped - And not all have yellow bellies
My Orangeglos don't have yellow bellies and are always very well striped, same as my Sugarlumps. My Ali Babas don't have stripes and don't get yellow bellies. Now, my Moon and Stars - They get yellow bellies.
The yellow tendril thing only applies to Muskmelons (what you call cantaloupes) and some European and Asian melons. Muskmelons are ready when they slip/fall off the stem though.
As for watermelons, I always wait til they stop growing, and tap them. Since my Orangeglos don't change color or anything, it's the sound that says. Mine I usually wait about 1 1/2 months - 2 months after they first formed, then tap them regularly to know when they're ready. A good one has a very deep, hollow sound. Also when patted, it feels kind of hollow too, almost as if it gives. An unripe one will have a higher "plink" sound, and will feel more solid.
I've only been growing watermelons for, well, a couple months now, starting this year (
) because I only now have a huge greenhouse (
our climate most definitely could not support a ripe watermelon!) - And every melon I've picked so far was just perfect.
